{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/21605"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/21605","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Effects of creep and shrinkage on the behavior of reinforced concrete gable roof hyperbolic-paraboloids","abstract":"Shell structures achieve a substantial contribution to their strength from geometry. Likewise, then as a corollary, some shells, will experience significant changes in their strength as a consequence of changes in their geometry that develope in response to loads. The special characteristics of concrete, as an aging viscoelastic material, allow the increase of deflections in time under constant load; in addition, concrete shrinks when drying, and consequently, stress redistributions due to geometric changes take place. It therefore follows that reinforced concrete shells built in certain configurations may experience problems due to time deformations.","abstract_html":"Shell structures achieve a substantial contribution to their strength from geometry. Likewise, then as a corollary, some shells, will experience significant changes in their strength as a consequence of changes in their geometry that develope in response to loads. The special characteristics of concrete, as an aging viscoelastic material, allow the increase of deflections in time under constant load; in addition, concrete shrinks when drying, and consequently, stress redistributions due to geometric changes take place. It therefore follows that reinforced concrete shells built in certain configurations may experience problems due to time deformations.","abstract_has_math":false,"creators":["Gallegos-Cazares, Sergio"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Civil Engineering","degree_department":null,"school":null,"contributors":["Schnobrich, William C."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T13:13:38Z","date_published":"2011-05-07T13:13:38Z","updated_at":"2026-07-22T22:25:18Z","subjects":["Engineering, Civil"],"languages":["eng"],"rights":["Copyright 1989 Gallegos-Cazares, Sergio"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI8916249","(UMI)AAI8916249"],"render_values":[{"text":"AAI8916249","href":null,"code":true},{"text":"(UMI)AAI8916249","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/21605","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Schnobrich, William C."]},{"key":"dc:creator","label":"Author","values":["Gallegos-Cazares, Sergio"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T13:13:38Z","10000-01-01","1989"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Civil Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Engineering, Civil"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1989 Gallegos-Cazares, Sergio"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI8916249","(UMI)AAI8916249","http://hdl.handle.net/2142/21605"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Shell structures achieve a substantial contribution to their strength from geometry. Likewise, then as a corollary, some shells, will experience significant changes in their strength as a consequence of changes in their geometry that develope in response to loads. The special characteristics of concrete, as an aging viscoelastic material, allow the increase of deflections in time under constant load; in addition, concrete shrinks when drying, and consequently, stress redistributions due to geometric changes take place. It therefore follows that reinforced concrete shells built in certain configurations may experience problems due to time deformations.","One class of shells which apparently has experienced more than its share of such problems is the shallow hyperbolic parabola. Several roof shells built in this configuration have suffered significant structural failure from five months to as long as fifteen years after their being placed in service.","In this investigation, a general finite element program is extended to consider time dependent and time independent characteristics of concrete in shell-beam structures. Cracking, concrete compressive nonlinearity, steel nonlinearity, and concrete-steel interaction are considered in the time independent model, while aging, creep and shrinkage are included in the time dependent one.","With the model implemented, a series of studies are developed considering the structural effect of several parameters on the time dependent response of gabled roofs. Among the parameters considered, the manner of constraint in the support, and the size and position of the crown beams are important. Decrease in the load carrying capacity level considering time dependent effects has been observed with a observed final strength of only 50% to 75% of that without any time variation, displacements are increased four to eight times from the time independent ones, and large stress redistributions have been found to occur with a shift in the load carrying mechanisms from membrane to flexural. Some apparently unimportant parameters like the crown beam positioning with respect to the shell have been found to have an important role in the structural response. Design considerations emerging from the numerical results are highlighted in an effort of improve our design criteria basis for this kind of structures.","Made available in DSpace on 2011-05-07T13:13:38Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 8916249.pdf: 11646591 bytes, checksum: ea9266f0879d215a3274876ca127f1ed (MD5) Previous issue date: 1989","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:51:58Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:23:53-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"]},{"key":"dc:title","label":"Title","values":["Effects of creep and shrinkage on the behavior of reinforced concrete gable roof hyperbolic-paraboloids"]}]}],"canonical_facts":{"dc:contributor":["Schnobrich, William C."],"dc:creator":["Gallegos-Cazares, Sergio"],"dc:date":["2011-05-07T13:13:38Z","10000-01-01","1989"],"dc:description":["Shell structures achieve a substantial contribution to their strength from geometry. Likewise, then as a corollary, some shells, will experience significant changes in their strength as a consequence of changes in their geometry that develope in response to loads. The special characteristics of concrete, as an aging viscoelastic material, allow the increase of deflections in time under constant load; in addition, concrete shrinks when drying, and consequently, stress redistributions due to geometric changes take place. It therefore follows that reinforced concrete shells built in certain configurations may experience problems due to time deformations.","One class of shells which apparently has experienced more than its share of such problems is the shallow hyperbolic parabola. Several roof shells built in this configuration have suffered significant structural failure from five months to as long as fifteen years after their being placed in service.","In this investigation, a general finite element program is extended to consider time dependent and time independent characteristics of concrete in shell-beam structures. Cracking, concrete compressive nonlinearity, steel nonlinearity, and concrete-steel interaction are considered in the time independent model, while aging, creep and shrinkage are included in the time dependent one.","With the model implemented, a series of studies are developed considering the structural effect of several parameters on the time dependent response of gabled roofs. Among the parameters considered, the manner of constraint in the support, and the size and position of the crown beams are important. Decrease in the load carrying capacity level considering time dependent effects has been observed with a observed final strength of only 50% to 75% of that without any time variation, displacements are increased four to eight times from the time independent ones, and large stress redistributions have been found to occur with a shift in the load carrying mechanisms from membrane to flexural. Some apparently unimportant parameters like the crown beam positioning with respect to the shell have been found to have an important role in the structural response. Design considerations emerging from the numerical results are highlighted in an effort of improve our design criteria basis for this kind of structures.","Made available in DSpace on 2011-05-07T13:13:38Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 8916249.pdf: 11646591 bytes, checksum: ea9266f0879d215a3274876ca127f1ed (MD5) Previous issue date: 1989","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:51:58Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:23:53-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"],"dc:identifier":["AAI8916249","(UMI)AAI8916249","http://hdl.handle.net/2142/21605"],"dc:language":["eng"],"dc:rights":["Copyright 1989 Gallegos-Cazares, Sergio"],"dc:subject":["Engineering, Civil"],"dc:title":["Effects of creep and shrinkage on the behavior of reinforced concrete gable roof hyperbolic-paraboloids"],"dc:type":["text"],"thesis:degree_discipline":["Civil Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:18Z"}